SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'aceb6dcb87d42c599caf17e2f7bbc180d1bbbee29ff196c7b6b14ef151f830fd' 
  AND token = '/MQzB0Xz/ZtqvFv1Hy/j7A3/VcAU9N9PW5Yp4vg+Osg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}